• 한국항해항만학회지
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• 제29권6호
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• pp.555-560
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• 2005

전체 시스템을 최적상태로 유지하기 위한 정보공유의 필연성 등으로 대다수의 제어 시스템이 디지털 제어 시스템으로 대체되고 있다. 이러한 디지털 제어 시스템이 원활하게 운영되기 위해서는 전통적인 점대점 연결방식이 아닌 네트워크를 기반으로 한 시스템이 필수적이며, 이러한 산업용 네트워크를 지능형 항만 물류 시스템에 적용하기 위할 연구가 최근 다양하게 이루어지고 있다. 본 논문에서는 NMEA 2000의 기반이 되는 CAN 프로토콜을 이용한 크레인 시스템의 타당성을 검증하기 위하여 단순화된 네트워크 기반 제어 시스템을 구현하였다.

• 한국멀티미디어학회논문지
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• 제19권8호
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• pp.1487-1497
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• 2016

Explosively growing service of digital multimedia data increases the need for highly scalable low-cost storage. This paper proposes the new storage architecture based on torus network which does not need network switch and erasure coding for efficient storage usage for high scalability and efficient disk utilization. The proposed model has to compensate for the disadvantage of long network latency and network processing overhead of torus network. The proposed storage model was compared to two most popular distributed file system, GlusterFS and Ceph distributed file systems through a prototype implementation. The performance of prototype system shows outstanding results than erasure coding policy of two file systems and mostly even better results than replication policy of them.

• Perspectives in Nursing Science
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• 제16권1호
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• pp.12-24
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• 2019

Purpose: This study examined the suitability of using text network analysis (TNA) methodology for topic analysis of academic papers related to nursing. Methods: TNA background theories, software programs, and research processes have been described in this paper. Additionally, the research methodology that applied TNA to the topic analysis of the academic nursing papers was analyzed. Results: As background theories for the study, we explained information theory, word co-occurrence analysis, graph theory, network theory, and social network analysis. The TNA procedure was described as follows: 1) collection of academic articles, 2) text extraction, 3) preprocessing, 4) generation of word co-occurrence matrices, 5) social network analysis, and 6) interpretation and discussion. Conclusion: TNA using author-keywords has several advantages. It can utilize recognized terms such as MeSH headings or terms chosen by professionals, and it saves time and effort. Additionally, the study emphasizes the necessity of developing a sophisticated research design that explores nursing research trends in a multidimensional method by applying TNA methodology.

• 환경영향평가
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• 제29권1호
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• pp.61-77
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• 2020

현재 국내 주요 공공수역은 국가차원 아래 체계적인 물환경 관리가 되어왔고, 특히 하천, 호소 등 생태계의 실태파악 및 대응을 위해 지속적인 모니터링 및 관리가 이루어져 왔다. 그 중, 수질측정망은 수질측정 주기가 8일에서 한 달 주기로 조사되는 반면, 자동측정망의 경우, 실시간 자료를 수집함으로써 일 데이터 자료를 제공하고 있다. 따라서 측정망 자료를 활용하여 동일한 수질항목에 대해 추세변화를 분석하고 통계적 방법을 통해 비교하였다. Mann-kendall test 결과 Water Temperature (WT)와 DO는 모든 지점이 통계적으로 유의하지 않은 것으로 확인되었고, 특히 TOC에서는 4개 지점, TN은 2개 지점, TP는 3개 지점, Water Temperature (WT)는 7개 지점, pH는 2개 지점, EC는 5개 지점, DO는 6개 지점에서 동일한 추세 경향을 보였다. LOWESS 분석 결과, TOC와 pH의 측정망 결과는 서로 다른 추세를 보이는 것으로 분석되었다. 지점별, 항목간 상관관계 분석결과에 따르면 안동댐하류-안동1 지점에서는 TP, 도개-산곡지점에서는 TOC, 고령(자동)-고령 지점에서는 pH, 적포-창녕 지점에서는 TP, 감천-감천2-1 지점에서는 TN, TP, pH, EC, DO 항목을 제외하고 나머지 항목에서 유의한 양의 상관관계를 보이는 것으로 분석되었다. 그리고 신암-상주2 지점과 남강-남강4 지점에서는 모든 항목에서 유의한 양의 상관관계를 나타내는 것으로 분석되었다.

• Wind and Structures
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• 제36권6호
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• pp.423-434
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• 2023

Aerodynamic force coefficients are generally obtained from traditional wind tunnel tests or computational fluid dynamics (CFD). Unfortunately, the techniques mentioned above can sometimes be cumbersome because of the cost involved, such as the computational cost and the use of heavy equipment, to name only two examples. This study proposed to build a deep neural network model to predict the aerodynamic force coefficients based on data collected from CFD simulations to overcome these drawbacks. Therefore, a series of CFD simulations were conducted using different geometric parameters to obtain the aerodynamic force coefficients, validated with wind tunnel tests. The results obtained from CFD simulations were used to create a dataset to train a multilayer perceptron artificial neural network (ANN) model. The models were obtained using three optimization algorithms: scaled conjugate gradient (SCG), Bayesian regularization (BR), and Levenberg-Marquardt algorithms (LM). Furthermore, the performance of each neural network was verified using two performance metrics, including the mean square error and the R-squared coefficient of determination. Finally, the ANN model proved to be highly accurate in predicting the force coefficients of similar bridge sections, thus circumventing the computational burden associated with CFD simulation and the cost of traditional wind tunnel tests.

• ETRI Journal
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• 제30권5호
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• pp.696-706
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• 2008

With the increasing need for intelligent environment monitoring applications and the decreasing cost of manufacturing sensor devices, it is likely that a wide variety of sensor networks will be deployed in the near future. In this environment, the way to access heterogeneous sensor networks and the way to integrate various sensor data are very important. This paper proposes the common system for middleware of sensor networks (COSMOS), which provides integrated data processing over multiple heterogeneous sensor networks based on sensor network abstraction called the sensor network common interface. Specifically, this paper introduces the sensor network common interface which defines a standardized communication protocol and message formats used between the COSMOS and sensor networks.

• 한국농공학회논문집
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• 제63권4호
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• pp.23-32
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• 2021

For agricultural water management, it is essential to establish the digital infrastructure data such as agricultural watershed, irrigated area and canal network in rural areas. Approximately 70,000 irrigation facilities in agricultural watershed, including reservoirs, pumping and draining stations, weirs, and tube wells have been installed in South Korea to enable the efficient management of agricultural water. The total length of irrigation and drainage canal network, important components of agricultural water supply, is 184,000 km. Major problem faced by irrigation facilities management is that these facilities are spread over an irrigated area at a low density and are difficult to access. In addition, the management of irrigation facilities suffers from missing or errors of spatial information and acquisition of limited range of data through direct survey. Therefore, it is necessary to establish and redefine accurate identification of irrigated areas and canal network using up-to-date high resolution images. In this study, previous existing data such as RIMS (Rural Infrastructure Management System), smart farm map, and land cover map were used to redefine irrigated area and canal network based on appropriate image data using satellite imagery, aerial imagery, and drone imagery. The results of the building the digital infrastructure in rural areas are expected to be utilized for efficient water allocation and planning, such as identifying areas of water shortage and monitoring spatiotemporal distribution of water supply by irrigated areas and irrigation canal network.

• 경영과학
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• 제32권3호
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• pp.29-36
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• 2015

In this research, we analyze the sensitivity of the network density to the estimates for the Bass model parameters with both theoretical model and a simulation. Bass model describes the process that the non-adopters in the market potential adopt a new product or an innovation by the innovation effect and imitation effect. The imitation effect shows the word of mouth effect from the previous adopters to non-adopters. But it does not divide the underlying network structure from the strength of the influence over the network. With a network based Bass model, we found that the estimate for the imitation coefficient is highly sensitive to the network density and it is decreasing while the network density is decreasing. This finding implies that the interpersonal influence can be under-looked when the network density is low. It also implies that both of the network density and the interpersonal influence are important to facilitate the diffusion of an innovation.

• 환경영향평가
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• 제30권2호
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• pp.75-88
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• 2021

본 연구에서는 금강 수계의 자동측정망 중 6개 지점을 선정하고, 이와 동일하거나 인근에 위치해 있는 수질측정망 지점을 대상으로 두 지점의 수질특성 파악하고 통계 분석을 통하여 상관성을 평가하였다. 또한, 수질 분석결과를 활용하여 수질 지수로 변환하고 등급으로 표현해 비교하였다. 연구에 필요한 자료는 최근 4년간(2016-2019)의 국가물환경측정망 데이터를 활용하였으며 수온, pH, EC, DO, TOC, TN, TP를 평가항목으로 선정하였다. 수질 분석 결과, 자동측정망과 수질측정망의 수질농도는 일부 측정값의 차이는 보였지만 대부분 지점에서 일정한 비로 변동하는 경향을 보였다. 항목 간 상관분석결과 수온, EC, DO 항목은 측정망간 상관성이 매우 높았고, TOC, TN, TP 항목은 기본항목에 비해 낮은 상관성을 보였으나 일부 측정망을 제외하고 0.7 이상(상관계수 r)의 높은 상관관계를 나타냈다. 수질 지수 분석결과 자동측정망 수질지수와 수질측정망 수질지수가 비슷한 경향을 보이는 것으로 평가되었으며, 두 결과 모두 하류로 갈수록 지수점수는 낮아져 오염도가 증가되고 있음을 쉽게 파악할 수 있었다.

• 대한간호학회지
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• 제53권6호
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• pp.635-651
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• 2023

Purpose: This study aimed to identify the main keyword, network structure, and main topics of the national petition related to "nursing" in South Korea. Methods: Data were gathered from petitions related to the national petition in Korea Blue House related to the topic "nursing" or "nurse" from August 17, 2017, to May 9, 2022. A total of 5,154 petitions were searched, and 995 were selected for the final analysis. Text network analysis and topic modeling were analyzed using the Netminer 4.5.0 program. Results: Regarding network characteristics, a density of 0.03, an average degree of 144.483, and an average distance of 1.943 were found. Compared to results of degree centrality and betweenness centrality, keywords such as "work environment," "nursing university," "license," and "education" appeared typically in the eigenvector centrality analysis. Topic modeling derived four topics: (1) "Improving the working environment and dealing with nursing professionals," (2) "requesting investigation and punishment related to medical accidents," (3) "requiring clear role regulation and legislation of medical and nonmedical professions," and (4) "demanding improvement of healthcare-related systems and services." Conclusion: This is the first study to analyze Korea's national petitions in the field of nursing. This study's results confirmed both the internal needs and external demands for nurses in South Korea. Policies and laws that reflect these results should be developed.